Improved assessment of mitral valve stenosis by volumetric real-time three-dimensional echocardiography

OBJECTIVES This study was performed to determine the feasibility, accuracy and reproducibility of real-time volumetric three-dimensional echocardiogra phy (3-D echo) for the estimation of mitral valve area in patients with mit ral valve stenosis. BACKGROUND Planimetry of the mitral valve area (MVA) by two-dimensional ech ocardiography (2-D echo) requires a favorable parasternal acoustic window a nd depends on operator skill. Transthoracic volumetric 3-D echo allows reco nstruction of multiple 2-D planes in any desired orientation and is not lim ited to parasternal acquisition, and could thus enhance the accuracy and fe asibility of calculating MVA. METHODS In 48 patients with mitral stenosis (40 women; mean age 61 +/- 13 y ears) MVA was determined by planimetry using volumetric 3-D echo and compar ed with measurements obtained by 2-D echo and Doppler pressure half-time (P HT). All measurements were performed by two independent observers. Volumetr ic data were acquired from an apical view. RESULTS Although 2-D echo allowed planimetry of the mitral valve in 43 of 4 8 patients (89%), calculation of the MVA was possible in all patients when 3-D echo was used. Mitral valve area by 3-D echo correlated well, with MVA by 2-D echo (r = 0.93, mean difference, 0.09 +/- 0.14 cm(2)) and by PHT (r = 0.87, mean difference, 0.16 +/- 0.19 cm(2)). Interobserver variability wa s significantly less for 3-D echo than for 2-D echo (SD 0.08 cm(2) versus S D 0.23 cm(2), p < 0.001). Furthermore, it was much easier and faster to def ine the image plane with the smallest orifice area when 3-D echo was used. CONCLUSIONS Transthoracic real-time volumetric 3-D echo provides accurate a nd highly reproducible measurements of mitral valve area and can easily be performed from an apical approach. (J Am Coll Cardiol 2000;36:1355-61) (C) 2000 by the American College of Cardiology.